CLIMATE OF DEHRA DUN Anand Sharma O. P. Singh M. M. Saklani CLIMATE OF DEHRA DUN Anand Sharma O. P. Singh M. M. Saklani Published by © Indian Meteorological Department Government of India Ministry of Earth Sciences Designed & Printed at Central Printing Unit, Office of The Additional Director General of Meteorology (Research),Pune PREFACE Weather and climate affect all aspects of life. The importance of Meteorology and climatology for economic and social benefits of the society is being realized increasingly all over the world. Actions in the field of agriculture, aviation, energy, industry, Landscape and Urban ecosystem designs require climatological information for planning and successful execution of the projects with a view to derive maximum advantage out of the climatological information. Apart from general weather information required by common man, hundreds of enquiries received by the , Meteorological Centre, India Meteorological Department from the general public, decision makers and the electronic and Print media are about current weather as well extreme weather conditions. Daily and weekly weather reports are prepared as a routine by the department. These summaries, however, do not readily provide answers to many of the general queries such as-“Was yesterday’s rainfall a record?” or “When January was so cold or August so wet in the Past?” Capital cities by virtue of their large populace and greater awareness generate most of these queries. Climate features of Dehra Dun have been described in detail in this publication to answer these queries and for facilitating day to day decision making. The booklet contains monthly summaries, divided into four seasons, describing the averages and extremes of temperature, rainfall, wind and humidity. Occurrences of different weather phenomena such as heavy rains, thunderstorms, hailstorms, dust storms, squalls and fog are described in detail to provide information as to how many of these phenomena occur on an average and what have been their highest occurrence in the past. The three national festivals of India (Independence Day, Republic Day and Gandhi Jayanti) and state day of Uttarakhand (9th November) are celebrated in Dehra Dun. The averages and extremes of weather on these days are given to provide an idea of the weather conditions on these days. My gratitude to Dr Krishna Kumar, Scientist –E, National Data Centre, Pune for his valuable inputs. I am thankful to Shri Abhinav Singh, Shri B.B. Lal, Shri Vishal Mani, Shri D.K. Verma, for their efforts in the compilation of data and shri Amit Pokhriyal for typing the script. My sincere thanks to the National Data centre, Pune, and Meteorological Centre, Lucknow for providing the required data. Dehra Dun 02 June, 2012 Anand Sharma O.P. Singh M.M. Saklani Foreword Climate of a city plays an important role in its all round development. Dehra Dun the capital of Uttarakhand is lying in the foothills of Mussorie, Climatological Normals, extremes, diurnal variation and information during different seasons find wide application in different sectors. It gives me great pleasure to present the booklet “ Climate of Dehra Dun”. It provides a summary of various climatological information pertaining to Dehra Dun to the users. I appreciate the efforts taken by the authors in bringing out this booklet. I am confident that the booklet will meet long standing demand of city planners, reserhers, farmers & tourists etc. New Delhi 02 June 2012 L. S. Rathore Director General of Meteorology INDEX Particulars Page No. Preface …………………………………………………………………………….… i Geographical Location of Dehra Dun ………………………………………………. 1 Physiographic setting of Dehra Dun ……………………………………………….… 2 General Climate of Dehra Dun ……………………………………………………… 3 Winter Season ………………………………………………………………………. 6 Summer Season …………………………………………………………………….. 21 Monsoon Season ………………………………………………………………….… 33 Post Monsoon Season …………………………………………………………….… 47 Weather on National and State Festival Days ……………………………………….. 59 Tables ……………………………………………………………………………….. 67 Annexure ……………………………………………………………………………. 70 Geographical Location Geographical Location of Dehra Dun Dehra Dun is the capital city of Himalayan state Uttarakhand. Dehra Dun is one of the oldest cities of India and became the capital city after the formation of the Uttarakhand state in the year 2000. Dehra Dun is famous for its picturesque landscape and pleasant climate and provides a gateway to the surrounding region. The capital once famous for Basmati rice, Litchi, tea gardens, Sal forests and water canals is fast deteriorating due to rapid unplanned development and expansion in the past decade. The landscape of the city has changed drastically and now basmati rice, Litchi, tea gardens, Sal forests and water canals are disappearing at a very fast pace and thereby also changing its microclimate. The land use land cover change along with development and encroachment in and around has also led to increased man-animal conflicts. Dehra Dun is made up of two words Dehra and Doon where Dehra is derived from the word camp and Doon is a term for the valley that lies between the Himalayas and the Shivaliks.The night view of the city from nearby Mussoorie hills is quite beautiful. The coordinates of Dehra Dun are 30 degree 19' North and 78 degree 03' East. The observatory was established on 01January, 1967 in the Geodetic and Research Branch campus of the Survey of India. -1- Physiographic setting of Dehra Dun District The Dehra Dun district is situated in the North West corner of the state. It is located between the latitudes 29 °58’ N and 31°2’ N and longitudes 77° 34’ E and 78° 18’E. The district is located on the foothills of the Himalayas. The district is bordered by the Himalayan range to the north, the Shivaliks to the south the Ganges to the east and the Yamuna river to the west. The Dehra Dun district has varied physical geography from Himalayan Mountains to plains. Raiwala is the lowest point at 315 meters above sea level, and the highest point is within the Tuini hills, rising to 3700 meters above mean sea level. The famous hill station Mussoorie and Chakrata are part of the district and lie in the lesser Himalayan ranges. The district is bounded on the north and North West by the district of Uttarkashi and in the east by Tehri and Pauri districts. In the west it is bordered by Sirmaur district of Himachal Pradesh and to the south are Haridwar and Uttar Pradesh’s Saharanpur disrtrict. Dehra Dun lies in the zone IV (High damage risk zone) as per the Earthquake hazard zoning of India. Fig 1: Location of Dehra Dun -2- General Climate of Dehra Dun Dehra Dun – The capital of Uttarakhand lies on the foot hills of the Himalayas .The distance from the sea gives Dehra Dun an extreme type of continental climate with the prevalence of continental air during major parts of the year. The meteorological observatory was established on 01 January, 1967 in the Geodetic and Research Branch campus of the Survey of India. However, as far as, quantum of rain is concerned it is comparable to coastal stations of Maharashtra. Mainly during the three monsoon months of July, August and September does the air of oceanic origin penetrate to this region and causes increased humidity, cloudiness and rain. Most of the annual rainfall is received in the months from June to September with July and August being are rainiest. Dehra Dun is one of the rainiest capital cities of India. The rainfall and temperature variations within the city are quite considerable due to altitudinal variation and local orography with presence of high Mussoorie hills. As per the India Meteorological Department classification, seasons in India are classified as Winter Season (January to February), Summer Season (March to May), Monsoon or South-West Season (June to September) and Post-monsoon Season (October-December).However, for the study of climate of Dehra Dun season are classified as 1. Winter Season (December to February) 2. Summer Season (March to May) 3. Monsoon or South-West Season (June to September) 4. Post-monsoon Season (October-November). The summers in Dehra Dun are moderately hot and winters very cold. The temperature may rise up to about 41 degrees Celsius in summers with all time high of 43.9 degree Celsius, though the average temperature is around 35-36 degree Celsius. There are about 1-2 days of heat wave when the maximum temperature of a day rises to 4-6 degree Celsius above the normal values. Though the winters are not bitterly cold on most of the days, the temperatures may fall to 1-2 degree Celsius for a few days in winters when the cold winds from the nearby Himalayan Mountains makes the winters severe. The all time low minimum temperature for the city is -1.1 degree Celsius. The winters are also marked by mist and fog on few days especially during night and early in the mornings and rarely till forenoon with bright Sun shine during the day. -3- Data used A meteorological observatory is functioning at the Geodetic and Research Branch campus of the Survey of India since 01 January, 1867 and represents the city condition of Dehra Dun. Daily meteorological data of this observatory have been used to arrive at the climatology for Dehra Dun. The climatology of rainfall, temperature, humidity and wind described in the following sections are based on 40 years period of 1971-2010. The data in regard to maximum winds / squall are not available due to lack of Dynes PT instrument. Similarly the data about visibility is also not available. The extremes of rainfall described are from the year 1869 to 2010 and those of temperature from 1901-2010. The data on weather phenomena are for a 10 years period of 2001 to 2010. The normals are based on the period 1971 to 2010. There are some gaps in the data received from NDC, Pune, where ever possible gap filling has been done based on information available at the meteorological centre, Dehra Dun. The annual march of maximum/ minimum temperatures and rainfall is given in Figure 2. It shows that the maximum temperatures are at their peak during the months of May and June. Though the temperatures start falling in the month of July, the fall is gradual till October. Both the maximum and the minimum temperatures decrease sharply from the month of October with January being the coldest month. The rainfall increases from the month of June with the onset of pre-monsoon rainfall activity. July and August are the rainiest months. Monsoon withdraws towards the end of September. The rainfall decreases drastically from the month of October with November being the driest month of the year. -4-